Nutraceuticals
The term nutraceutical was introduced in the 1990's by Dr. Stephen De Feliceas: “A nutraceutical is any substance that is a food or a part of a food and provides medical or health benefits, including the prevention and treatment of disease. Such products may range from isolated nutrients, dietary supplements and specific diets to genetically engineered designer foods, herbal products, and processed foods such as cereals, soups and beverages”.
Health Canada defines nutraceutical as: “a product isolated or purified from foods, and generally sold in medicinal forms not usually associated with food and demonstrated to have a physiological benefit or provide protection against chronic disease”.
Diacylglycerol (DAG)
In refined edible fats and oils, triacylglycerol (TAG) content generally exceeds more than 95%. Although a minor component, the levels of DAG can be as high as ca. 10%, in some edible oils depending on the source. In humans, DAGs are produced as metabolic intermediates after ingestion of TAG, namely 1,2 (or 2,3)-diacyl-sn-glycerol (1,2-DAG). In contrast, DAG is present as 1,3-diacyl-sn-glycerol (1,3-DAG), in the cooking oils which are generated from 1,2-DAG due to heat treatment during the manufacturing process by migration of the acyl group. 1,3-DAG can also be produced by an enzymatic process with 1,3-specific lipase In addition, substantial amounts of DAG can be generated during frying of foods due to hydrolysis of TAG. Edible oil containing more than 80% DAG dominated by 1,3-DAG, commonly known as DAG oil, is commercially produced by specific lipases from edible fats and oils. Food energy content of DAG oil has been shown to be slightly lower than that of TAG oil. Chemical structures of TAG and DAG molecules are shown in FIG. 1.
DAG oil (1,3-DAG) is, in contrast to TAG, mainly utilized by the body as an energy source, rather than being stored, due to the different metabolic fates after absorption into the gastrointestinal epithelial cells. Clinical studies with animals and humans on the effects of DAG oil have shown significant decrease in body weight, thus reducing obesity-related health risks. DAG oil has been shown to be useful for patients with type 2 diabetes to prevent atherosclerotic diseases. Extensive studies have been conducted on the safety aspects of DAG consumption and no adverse effects have been reported of DAG consumption. DAG oil has been introduced in Japan in 1999 as healthy cooking oil, and in 2000, the FDA of USA stated that DAG oil was generally safe. Prepared from fats and oils, DAG is also used as emulsifiers as direct food ingredients.
α-Lipoic Acid (IA) and Dihydrolipoic Acid (DHLA)
Commercially available alpha-lipoic acid (racemic alpha-lipoic acid) is a synthetic product consisting of two forms, the R+ and S− optical isomers in equal amounts. The R+ isomer is the naturally occurring lipoic acid. This isomer (R+) is the type the body makes and requires for its efficacy. LA has been in use as a multi-tasking supplement and is popularly known as “metabolic antioxidant” or “the universal antioxidant” since it recycles vitamin C, Vitamin E and glutathione in the body. The body needs LA to produce energy in the mitochondria. In addition, LA is converted in the body into dihydrolipoic acid (DHLA), which acts as an additional antioxidant. LA is soluble both in water and fat resulting in activity both in lipid and in aqueous phase. This interesting bioactive compound has been used to treat peripheral nerve degeneration, lower cholesterol, detoxify the liver, and control blood sugar levels of the diabetics. Additionally, LA has been found to help in protecting the functionality of the mitochondria, and thus being effective against ageing.
It has been suggested that lipoic acid could be the drug of the future based on the experimental and clinical studies with drugs containing lipoic acid. It has been particularly emphasized on the antioxidant properties of LA/DHLA system for scavenging of the reactive oxygen species (ROS), chelating metal ions and regenerating cellular antioxidants. DHLA is the reduced form of LA which possesses superior antioxidant property compared with its oxidized form LA as obvious from their chemical structures. And both of these compounds have been demonstrated and suggested to be useful in treatment in a variety of pathological conditions linked to oxidative stress e.g. diabetes and cardiovascular disease, liver diseases, AIDS, age-related disorders, multiple sclerosis, Alzheimer's disease, diabetic polyneuropathy, diabetic neuropathy etc. The synergistic effect of DAG oil and phytosterols has shown higher cholesterol lowering property compared with TAG oil and phytosterols. Phytosterol lipoate and conjugates of lipoic acid with glycerol have been the subject of patent applications, namely WO 01/66560 A2; WO 2009/086547 A1; and JP 2007-077066.